Who to follow on Twitter? Iranian President Hassan Rouhani

In this Sept. 10, 2013 photo released by the official website of the office of the Iranian Presidency, Iranian President Hasan Rouhani speaks during an interview with state television at the presidency in Tehran, Iran.

By Robert Windrem, Investigative Reporter, NBC News

Iranian citizens may not be allowed to use social media, but new Iranian president Hassan Rouhani has used his personal Twitter account to express political opinions that break with the hard line of his predecessors – and attract the rapt attention of U.S. diplomatic and intelligence officials.

Rouhani surprised the world by wishing the world's Jews a happy Rosh Hashanah earlier this month, but his account had already become a must-read for current and former U.S. officials, as some of them readily admit, after he used it to condemn the August chemical weapons attacks in Syria.

"His outreach on social media is one of many signs that he wants to lead Iran out of its isolation," said P.J. Crowley, a former assistant secretary of state and National Security Council advisor. "You can say a lot in 140 characters."

More than one official has sent Rouhani questions through Twitter. He has yet to respond.

Rouhani, who began using the account during his campaign, now has 43,000 followers, and Iranian officials confirm that the Tweets are his thoughts, even if the keystrokes aren't. His affection for the medium is ironic, given that other than a brief two-hour period earlier this week, the Iranian government has tried to block social media ever since the failed Green Revolution of 2009.

Rouhani told NBC News' Ann Curry Wednesday that he hopes to establish a commission to establish new norms for social media for the "protection of our national identity and on our morals."

He then took to Twitter to make sure sure his followers knew of his interview with Curry. First he tweeted that the interview had taken place, noting it was "exclusive":

Rouhani first attracted wide U.S. attention with tweets in late August, just weeks after his inauguration, about the chemical weapons attacks outside Damascus that killed 1400 civilians.

Without assessing blame, he said Iranian officials "completely and strongly condemn the use of chemical weapons in Syria," and urged the international community to "use all its might" to prevent more attacks, a seeming endorsement of military action:

We completely & strongly condemn use of chemical weapons in #Syria because Islamic Republic of Iran is itself victim of chemical weapons 1/2

Rouhani has also used Twitter to show that he rejects some of the domestic policies of his predecessors, including the persecution of anti-regime activists during and after the Green Revolution. Earlier this month, when his government announced the release of some of those dissidents, many held for years, he retweeted the names.

Most interesting was his decision to retweet a photo of human rights lawyer Nasrin Sotoudeh, reunited with her family on Tuesday after three years in prison:

Other tweets about domestic affairs have also caught U.S. interest. On Wednesday, he advised the Islamic police to take it easy on women, "once again" urging them "to respect human #dignity &avoid radical conduct in pursuing matters related to #Islamic covering":

Once again President #Rouhani urges Police to respect human #dignity &avoid radical conduct in pursuing matters related to #Islamic covering

He also made it a point Sunday to congratulate the first Iranian woman to participate in the world championships in triathlon, using the hashtags #forward #hope #equality #progress #pride and #GenderEquality" in a series of tweets.

Last Thursday, he advised that the Iranian House of Cinema, the national film academy, had reopened after being shut by "hardliners":

Perhaps most surprising, earlier this month both he and his foreign minister, Javad Zarif offered "a blessed Rosh Hashanah" via their Twitter accounts to "all Jews," presumably including those in Israel:

His predecessor's most famous public pronouncements about Jews were repeated expressions of doubt about the Holocaust.

Crowley said that Rouhani's tweets are positive signals, but they can only "chip away" at the huge divide between the Iran and the U.S. "Any serious negotiation would involve a lot more than 140 characters," said Crowley. "It will try everyone's patience and then some."